Hi Guys, bit baffled by something at work. We recently bought a new desktop running Windows 8.1 Pro on an i7 4790, 12GB RAM etc. to be used for some graphical work. After going through the usual initial Windows config I connected it via cable to an RJ45 port and a number of other PC's in the office lost network connectivity. At first I didn't think it was the PC doing it. Thought it was something else but after a while of trying a few different things a colleague and I narrowed it down to that PC. Whenever it's plugged into the network it does something which is only resolved by restarting the switch (24 port, unmanaged). There are actually 3 switches in use, all 24 port and all unmanaged but only PC's sharing the same switch as the new PC lose their connectivity.
We also noticed that it has some sort of knock-on effect to the two Cisco routers which act as a gateway and provide internet. They seem to freeze. Again, at first we thought it was a router problem, but we determined that it is restarting the switch which solves the issue, not the routers.
We do have one other Windows 8.1 PC on the network and it's been fine.
I've tried disabling IPv6, and also the wifi and bluetooth which came built-in with the PC.
None of the other adapter options look particularly odd so I haven't changed anything but I suppose it could be some sort of Windows 8.1 networking function, or adapter function, which is interfering.
Anyway, I'm slowly coming to a loss on this one, and wondering if anyone had any bright ideas?
Thanks.